Engine Cooling: electric driven fans vs engine driven fans

[Sergei]

Ok, i thought its time to start own thread for this stuff.

So gasket thread with help of Joey and Charles made me think again about second attempt of replacing engine driven fan. Seems like favorites in US (presently) are Flex-a-lite model 210. However they seem to have model 295/298 which is actually better and nearly 1:1 matches Kenlowe kit which is favored in EU (and cost you arm and leg if you try to buy it at present exchange rate)..

Which one to choose?

Now often disputed reason to go electric so to release some horses, but its actually not quite true, at least for people with stock alternators - increased draw will cause engine to work harder. Folkz who got mean green (and i am one of them) seems to be better equipped for such swap.

So horsies aside - what would be electric gain?
- better control over wading (can shut it down)
- you actually know when its engaged or not (to see that for engine driven one you has to open hood while truck running ).
- no more swaps for viscous coupling (relative pro, b/c price of coupling is not that high if you go aftermarket ($170 tops), and its not like you swapping it every two years).
- more space in engine compartment - definitive plus as it will also effectively increase air flow inside compartment, thus - cooling. But increase is not that big to notice, i think
- less wear on water pump. Well again - at 90$ (yep. there are finally cheap ones. Just when i replaced mine.. bastards ) its all relative. You aint gonna swap it every two years, arent you?
- allegedly airflow is better, but there seems to be no CFM information whatsoever on engine driven fans. Anyone got any information? Please?
- airflow is constant and way better while offroading - if above is true. Thing is - you not really pushing RPMs of engine above 2-3K while doing normal offroading. So if you moving at slow pace (and normally we all do, or trail gets damaged) - flow from engine driven fan isnt all that great. Electric however can be engaged all the time and not reall dependant on your speed. So it may be better.

Thats it really..

Now bad things with electrical stuff
- you need serious installation. Inch of space between surfaces will decrease efficience drastically (and how i know? )
- you need real fan kit. Cheapo imperial stuff from your Checkers autostore wont do, even though it will be rated at 3K CFM (i been there, seriously. Single fan wont work)). Real kit costs like 260-360$ (depending on model). Or similar numbers in GBP for Kenlowe.
- you putting extra drain on electric system
- there are more electric gremlins to hunt
- better airflow with normal road use is very questionable (again, i like to be prooved wrong, but i failed miserably to find CFM information on engine driven fan)

Yet, i cant get idea from my head.. And its VERY bad time b/c i need to replace cat. convertors and exhaust...

 

[joey]

Just my thoughts on this....first at normal road speeds above 45 mph you don't even need a fan... road speed will cool the radiator enough unless you are pulling a trailer up a hill in 3rd gear.

I have a Flex-a-lite 295/298 and let me give you a small hint, with out some fun mods it will not fit. Basically I have to extend the lower radiator hose pipe, the curved part (metal) that goes into the radiator in order for it to even think about fitting. You will not have much space between the radiator and the "S" belt once installed maybe 3" if I recall from my test fit. Basically just enough to change the belt.

But you are correct at trail speeds and city type driving it will cool you Rover much better than your clutch fan.

 

[Sergei]

Thanks for hint Joey, i'll look at that tube..

Thing is - 298 isnt that much wider than 210 (2.6" vs 4") but it puts through much more air, which is always good thing. And price is about same.